since they always need a C compiler, even when the source code is
completely in C++.
For some other packages, stated in the comment that a C compiler is
really not needed.
without affecting packages that are currently using it.
Packages which previously didn't set BUILDLINK_DEPMETHOD to neither "full" nor
"build" now set it to "full", but should be checked whether they really need it
(comment added). Packages which previously set it to "build" now don't set it
anymore.
Ok by jlam, wiz.